Copper-clad iron and steel.



skilled in the art to which it appertains to UNITED STATES PATENT OEEIOE.

JOHN iMONNOT, OF NEW YORK, N. Y., ASSIGNOR TO DUPLEX METALS COMPANY, OF NEW YORK, N. Y., a CORPORATION OF NEW YORK.

OOPWLAD IRON STEEL.

Patented July 21, 1908.

No. 893,932. Specification of Letters Patent.

application fled October 6, 190,6, laid Io. 881,880. Divided and this application fled. Iobnury 18, 1007.

Serial No.

To all whom it may concern:

Be it known that 1, JOHN F. MONNOT, a .citizen of the United States, residing at New York, in the county of New York and State 5 of New York, have invented certain new and useful Improvements in Copper-Clad Iron and Steel; and I do hereby declare the following to be a full, clear, and. exact description of the same, such as will enable others make and use the same.

This invention relates to clad metals and consists in compound bodies of ferrous metals anibbopper permanently and indissolubly welded together, the said copper generally being in'the form of a thin layer or stratum ,of dense, non-porous, impermeable characteristics, welded to and carried by the ferrous metal and relying upon it for support; allas more fully hereinafter set forth and as claimed.

Y High-melting malleable non-ferrous metals and non-ferrous alloys of the copper and noble metals grou s, or such high melting metals as have litt e or no aflinity for carbon (for example, do not readily form carbids), do not readil unite together with the unlike ferrous meta s, (or the metals forming carbids), in a union analogous to a weld-union; and despite the many attempts heretofore made in the art, such a union has not been considered practicableby those skilled in the art. As a rule it is considered that only like metals will weld together, and ferrous metals and the stated non-ferrous metals are too unlike, it has been believed, for a true weldunion. This I have discovered is erroneous, and by the use of proper methods, unions which are, or are closely analogous to,-welds, may be readily produced between bodies of ferrous metals onthe one hand and'such unlike metals as cop er, silver, gold, aluminum, the various cupri erous'alloys such as commercial gold and silver, brasses, bronzes, and the like. These non-ferrous metals are all malleable and of comparatively high melting point, viz., above 900 F., and therefore when united with steel the com ound body "formed may be worked at near t e Ordinary steel working temperatures, thereby rendering it possible to unite'the steel and nonferrous metal in the form of a billet and coextend them in any manner desired, as by drawing, rolling and the like, to 'form finished articles. This 0 ration Offers many advantages in point 0 costand simplicity, and furt er produces-hardened, compacted, dense, non-porous and im ermeable coatings of the coatin metals. T e two unlike metals bein per ectly welded, such co-extension is feasib e to any do ee desired without separation and in the finished article the coating metal maybe in as thin a film as is desired. With aweld union subsisting between the two metals, the coating metal can rely on the ferrous metal for suppplgt and it is not necessary as heretofore in t art with less perfectly united metals, to have the coat-v ing metal as a layer of suflicient thickness to sustain itself by its own strength.

The metal of the extended coatin is in asomewhat different condition from t e same metal extended as a sin le body, being roportionately much har er and denser t an such metal. In ordinary cold-drawn or cold- 7 5 rolled copper,.for example, onl a relatively thin exterior layer is hardene the interior portion of the metal being as soft, or nearly as soft, as before. This is because, in extending a single metal, practically all the hardening vactlon of the rolls or dies is confined to exterior layers; interior layers, removed from the action of the tool, acting, so to speak, as a cushion, so that the hardening does not extend inwards very far and so that such interior layers are practically speaking, not hardened at all; but in the case of the coextended clad metals herein described, theinterior ferrous metal, being relatively hard as compared with the metals employed as ooatings, and the coatings being relativel thin,

in coextension the softer metal un ergoes compression between the harder and stlffer core metal and the rolls or dies with an effect much the same as if it had been compressed from the inside as well as from the outside, so that, when the coatin is not too thick, the rolling or drawing har ens the layer of 008A).

ing metal nearly'uniformly throu hout. The layer is in mass what the ordinary harddrawn metal is in its superficial layers. Moreover, in clad metals of the character here described the coating is considerably strengthened and hardened by its molecular ,union or coherence with the base metal. the

latter actin as a stiff and strong backing supportin it at all points; and particularly so when t e coextension has been carried so far as to make the coating filmiform. The thin coating of even such a soft metal as copper being welded at its base to the supportin steel and being too thin to permit latera yielding, and being furthermore compacted and hardened by said drawing or rolling, behaves as if ofrelatively stiff, strong metal.

In the prior art ferrous metals have not been coated with awelded-on stratum of nonferrous metal having these characteristics, and indeed most coated ferrous metals have been produced electrolytically. Electrolytic coatings, however, as of copper for instance, are not impermeable, pores'or lines of separation always existing between the precipitated crystals, nor are they so unitedwith the base as to stand coextension with it. For this reason electroplating is usually done in the finished article, each such article being separately treated. The cost of this is obvious. Many attempts have been made toproduce east-on coatings-of copper and the like or steel, but these have been uniformly unsuccessful in attaining the desired ty e of union. Copper and like metals w' not unite in a coherent union with ferrous and like metals at the ordinary casting temperature of the former; they will at most merel adhere with a union easily broken. Sue coatings are, so to speak, merely stuck on, and they will stand no strain or stress, and though the 'oinedmetal in some cases can be co-extende to a limited degree, such coextension is not ra cticable beyond the point where the thic mess of the coating metal is sufficient to sustain itself by its own strength,

\ nor, core and sheath not being welded toether so as to compel uniforn coextension,

0 such coated metals extend together in such manner as to preserve their original ratio. Copper and steel, for instance, in a wire will be of different relative thicknesses in different places in such wire. I have, however, discovered that this lack of affinity between the ferrous metals on the one hand and the high melting non-ferrous metals on the other,-which exists at the melting or ordinar casting temperature of the latter, vanis es when the non-ferrous metal is heated to a degree relatively high above its melting oint. At temperatures several hundred e ees above their melting points and above t eordinary castin temperatures, the character of these meta s under oes a change and. they now display a marke affinity, chemical or physical, for the ferrous metals and substantially pure, substantially homogeneous bodies of these metals may be readily united thereto. For lack of another name Ihave called this theksupermolten condition. In the case of coppenwhich melts at about 1920'F. the supermolten temperature is aroun and above 2550.F.- That of silver is in the same neighborhood; that of aluminum somewhat lower, and that of gold somewhat higher. In another a plication Sr. N o. 281,680, of whichthis is a ivision, I claimed broadly a rocess of uniting these unlike metals foun ed on this henomenon;

said process bein now broady claimed-in mentari y contacting a cleaned steel in ot 7 with a mass of su ermolten copper or simi ar/ metal, thereby orming on its surface a firmly cohering. film of such metal; this film coherin with a tenacity which renders it,

impossi le to strip it with a cold chisel or so similar'cutting tool or to loosen it by expansion and contraction due to heat as by heating and quenching. To the copper-filmed surface so formed further copper may be united at the ordinary casting temperature, 5

or sufficient copper may be taken directly from the bath of supermolten metal producing the film to make a coating of the thickness desired. In the case of such cupriferous alloys as brass and the various bronzes which will not stand heating to the supermolten temperature, the coating may nevertheless be formed in a similar way b the use of an expedient. The steel may e filmed with copper in the manner described and then brass or bronze at a convenient temperature may be cast against the so filmed surface. Copper being like in nature to the cupriferous alloys stated, union takes lace between them without difficulty. Si ver, gold and aluminum are applied in exactly the same manner as cop er.

A compoun billet with a ferrous metal core formed from any of these metals in the manner described will be found to have a union of the joined metals so intimate and perfect as to defy rupture by any change in temperature short of a fusing heat. A copper steel billet of this character may be heated red hot and dropped in a barrel of water without the slightest disturbance of union and the same is true of the other joined metals described. This is a test which no rior article in this art has ever withstood.

t is only because the union between the metals is in the nature of, or analogous to, a true weld that my joined metals are enabled to withstand this extreme test. Metals merely stuck together, as in the prior art,

will at once separate when subjected to the test. Furthermore, in such a billet on attempting to cut apart the joined metals with a cold chisel the tool absolutely refuses to follow the line of union, going off into the soft metal. -Upon fiexure to rupture of a 1? thin piece of the joined metals, the break will take place either in the copper or the steel but not alon their line of union. The bounding film- 'ke layers between the abutting surfaces ofthe two metals appear to be 13.7

resent exceptionally strong, lendin some support to the theory that there may e an extremely tenuous joining layer of a strong and tenacious alloy between the two metals, though'to the eye the masses of copper and steel, having their ordinary appearance, seem to join directly. In priorarticles made in this art a cold chisel readily finds the line of demarcation between the joined metals. A steel billet clad with three per cent of coppermay be easily extended to the thinnest wire even to wire of hairlike thinness without separation of the two metals and with substantial preservation of the original ratio between them. In attempting to make wire of the articles of the prior art, co-extension was only possible so long as the copper remained in sufficient thickness to form a tube strong enough to sustain itself; it could not rely upon the steel core for support as does the welded-on three percent. copper film of fine wire such as 39 gage wire, made from drawn-down bodies of the metal of the present invention. What is't'rueof copper on steel is also true of the other non-ferrous metals stated when united to steel. These non-ferrous metals may also be united to metals of the iron-like group such as nickel, cobalt, etc., in the same manner.

Li uids and set liquids are devoid of pores and the non-ferrous metalsbeing ut on the ferrous base in a liquid condition, t e coating is absolutely poreless. In the co-extension of the 'oine'd metals which is usually racticed, tliis coating is further compactet and hardened, such compacting and hardening taking place in the interior as well as in the exterior layers'of the coating, as previously explained and the underlying steel base is hermetically sealed from outside influences and cannot corrode or chan e. A coppersurfaced steel body therefore 1218 at once the strength, stiffness and resilience of steel and the desirable surface ofco per, combining the advantages of both metals.

Brass clad and bronze cladsteel made according to said process are very advantageous for many, purposes where the strength and cheapness of the ferrous metal and the appearance of the cupriferous alloy are required, as in the metal fixtures of trolley cars, bedsteads, telephone arts, scientific instruments and a myriadotlier uses. Such clad metals may have a minimum thickness of the relatively expensive coating metal and Ketbe of long life, the cupriferous alloy being ard and dense, and thoroughly supported by the underlying metal to which it is welded in a manner precluding exfoliation. Its com actness, homogeneity, continuity and free om from pores, blowholes, etc. prevents moisture and gases penetrating to corrode the underlyin steel and lift the coating in the manner fami iar with electroplated ware. Such cupriferous alloys however must ordinarily be applied with an intermediate layer of a me, heat-resisting metal such as copper or a uminum, referab y the former, thou h an aluminum-ii .wet by cast-on brass or'bronze and may be used to secure the desired weld-linkin between the steel and the cupriferous al oys.

lmed steel surface is readi y Coin gold and silver, and baser alloys of the same metals of course contain copper and may be readily welded to a copper filmed surface if desired, though these cupriferous r alloys will withstand heat sufficiently to ermit a direct application in the su' ermo ten state. Such cupriferous alloys as t e brasses composed in various proportions of zinc and copper, and the bronzes, containing copper and tin in various proportions, as well as the ternar alloys of copper, zinc and tin, however, 0 not well withstand the supermolten temperature, the zinc or tin burning'out. Aluminum bronze though less sensitive to the supermolten heat may also be advantageousl applied with an intermediate linking 11m 0 copper or aluminum, as this permits working with the alloy at lower temperatures.

In another and co-pending application, Ser. No. 368,77 0,'filed April 17, 1907, I have described and claimed methods of uniting cupriferous and other alloys to ferrous metals by means of a linking layer of a high-- melting metal as well as metal bodies comprising metals so linked.

One im ortant product which may be made by tl ie methods described in my above mentioned applications and which embodies the invention of this case, consists of very pure iron or steel, containing practically no carbon or' other metalloids, but coated with co per, aluminum, silver, gold, bronzes, or 0t er coating metals. Such pure iron or steel may be produced by the Tropenas process, for example, by carrying the operation to the polnt of substantially complete elimination of the metalloids, and before the steel commences to burn, removing it from the converter. Such steel is very soft and ductile and malleable and has high electricalconductivity, but is extremely apt'to take upoxygen and other impurities. By the methods of handling and heating which may be employed in carrying out the process in my said applications, I can handle ingots or cores of such pure metal without oxidation or other contamination thereof, such pure metal being sealed in against contamination and once the coating of copper or other metal is applied to such an ingot or core, the coating protects the pure core metal from oxidation etc. Because of the extreme ductility of this pure steel, the clad ingots made from it may be extended to the most extreme thinness, thus makin -practicable the use of such material for foi tinsel, gold leaf, silver leaf, etc. In rolling out ingots or plate with cutters having a rather rounded edge, in lieu of the usual sharply triangular one, the steel and the copper cut differently, the copper flowing a little before the tool and inclosing the edge. A sufiicient union between the meeting edges of copper. so

brought into contact may be secured by the use of the usual burnishing and s inning tools. I have filed an application escribing and claiming this met 0d of covering the cut edges, such application being Sr. No. 303,916.

The relative ratio of the joined metals may be as desired, three per cent. being usually sufficient for copper clad steel for .most purposes Where the coextension is not carried too far. With brass clad and bronze clad steel this thickness is also usually sufficient.

By the term non-ferrous metal, as used herein, I mean metal which is so unlike iron or steel in chemical and physical roperties as not to be ordinarily considered an ironlike metal, and which does not readily unite 'with or weld to iron by ordinary methods;

also alloys containing no iron, or at most but very small amounts and not exceeding 1 per cent. or so.

In an application filed June 19, 1908, Sr. No. 439,284 I have claimed compound or clad metal articles comprising a coating of copper, silver, old, aluminum and like metals, alloyed wit ferrous metals, weld united to ferrous metals, and a process of making such articles.

In this application I claim only the product comprising ferrous metal and copper united as above described; copper being understood, as above explained, to be metal of commercial rades, ranging from the pure metal throug so-called electrolytic metal to metal not containing more than 1 per cent. or so of iron and like proportions of other impurities. In application filed Apr. 13', 1907, Sr. No. 367,985, I have claimed a product comprising silver united to ferrous metal as described; in application filed Apr. 13, 1907 Sr. No. 367,986, I have claimed a product comprising gold united to ferrous metal as described, with or without an intermediate metal; in application filed Apr. 23, 1907, Sr. No. 369,995, I have claimed a product comprising silver united to ferrous metal by an intermediate metal; in-application filed Apr. 23, 1907, Sr. No. 369,997, I have claimed a product comprising a light-metalgroup metal (aluminum for example) united to a ferrous metal with or Without an. intermediate metal; and in various other applications I have claimed other products com-- prising weld-united unlike metals.

What I claim is 1. As a new article of manufacture, a ferrous metal base having a welded-on, continuous, poreless, dense'coating of copper united thereto by a union resisting temperature changes, cutting tools and mechanical stresses, said coating having the properties of metal set from a liquid state.

2. As a new article of manufacture, an extended metal article comprising a ferrous metal base and acontinuous, oreless, dense coating of copper weld-united thereto, by a union resisting temperature changes, cutting tools and mechanical stresses, said ferrous base and copper coating having been extended together.

In testimony whereof I affix my signature, in the presence of two witnesses.

JOHN F. MONNOT.

Witnesses:

ROGER H. LYON, H. M. MARBLE. 

